RE: L'origine et l'évolution des oiseaux, with a

[Tim Williams <tijawi@yahoo.com>]

David Peters wrote:

> > Longisquama and Sharovipteryx are "terrestrial
> > predators that were fleet-footed hunters" now?
> 
> 
> Well, let's put it this way... they were not eating
> plants...right? 'Predators' are not just predators
> of vertebrates.


I think it was more the "terrestrial" and "fleet-footed" adjectives that were a 
little startling, more so than "predator" and "hunter".  


Even if _Longisquama_ and _Sharovipteryx_ targeted insects or worms, I guess 
they could be called "hunters".  The insects and worms would certainly think 
so.  I won't quibble this point.


> As for your thought experiment, kites are made of stiff
> paper, crossed strips of wood and string. How is this
> analogous?


I once had a kite made of plastic.  It was soft and flexible - which was good 
for both of us when it fell out of the sky on to my head.


> As for Sharovipteryx, the membrane trails the leg, extends
> something like a Japanese paper fan (were you thinking this
> and wrote that?),


No.

But since you bring it up... strap two large Japanese paper fans to your legs 
and see how fast you can run.  Give it a try!  I'm not talking about a thought 
experiment here.  Go to your local park and try it out!  Bring a stopwatch with 
you.  And a measuring tape too, to see if your leg-fans improve your jumping 
prowess.  Put your experiment on YouTube - I'd like to see it.


> and thus it reduces drag (think of biplane
> wires vs. struts) while remaining fully collapsible. With an
> elongated ilium and a tibia longer than the femur, and tiny
> forelimbs, Sharoviptryx is a classic bipedal
> cursor/saltator.


I wouldn't have equated "classic bipedal cursor/saltator" with having kite-like 
or fan-like patagia attached to the hindlimbs and tail.

 
> With regard to the 'missing' hindlimbs of
> Longisquama, you also can rely on phylogenetic bracketing.


I'm sure _Longisquama_ had hindlimbs.  I'm not sure they were long.  I'm also 
not sure that phylogenetic bracketing tells us so in this case.

BTW, did you use hindlimb characters from _Longisquama_ in the matrix for your 
phylogenetic analysis?


Cheers

Tim